1. Field of the Invention
The present invention relates to a mechanism for controlling contact and separation between photosensitive elements and a belt of an image forming apparatus.
2. Description of the Related Art
Among conventional technologies related to a mechanism for controlling contact and separation between photosensitive elements and a belt of an image forming apparatus, for example, Japanese Patent Application Laid-open No. 2003-186313 discloses a contact-separation mechanism using a cam. Japanese Patent Application Laid-open No. 2001-337497 discloses a technology in which a pinion gear is additionally used as a braking member to absorb impact caused by the operation of a contact-separation mechanism. Japanese Patent Application Laid-open No. H8-339129 discloses another conventional technology in which a braking member (a buffer material) that comes into contact with an outer periphery of an eccentric cam is arranged in a transfer belt unit that includes a driving unit (a main motor) for rotating the cam. In this conventional technology, because the braking member is mounted on a swinging lever, the cam and the braking member are in contact with each other all the time, which leads to a larger driving torque of the cam, and an increase in cost and apparatus size.